From seeds to sprouts: the effects of whole-genome multiplication on clonal and sexual reproduction in Pilosella rhodopea

Agnieszka Adamska ¹

Department of Botany, Faculty of Science, Charles University, Benátská 2, 128 01 Prague, Czechia; Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta 9, 845 23 Bratislava, Slovakia ¹

Polyploidy occurs when an organism has more than two complete sets in somatic cells. It’s one of the most important evolutionary drivers that may lead to the formation of evolutionary novelties. Polyploidy is categorized into two types: allopolyploidy, which means that subgenomes are made from different parent species, and autopolyploidy, when the subgenomes are derived from a single parent species through genome multiplication. Autopolyploids often struggle with reduced fertility because of disturbed meiosis. This means that their sexual reproduction can be limited. However, some plants deal with this problem through enhanced clonal reproduction. It is unknown if the increased clonal growth is directly caused by polyploidization, what are its underlying genetic and physiological factors, and finally what is the ecological impact of such reproduction shift between closely related cytotypes. Understanding the consequences of polyploidy in the model system of Pilosella rhodopea (Asteraceae) can shed light on how autopolyploids establish and persist in nature. Pilosella rhodopea is a diploid–autopolyploid complex, with up to five ploidy levels (2x–6x) that occur in numerous mixed-ploidy populations. Its contact zone, in the Balkans, is believed to be the biggest primary diploid-autopolyploid contact zone ever recorded in angiosperms. Pilosella rhodopea is a perennial species forming accessory rosettes from hypocotyl meristems but additionally can reproduce clonally via root sprouts. It has been documented that with higher ploidy levels the sexual reproduction decreases, while clonal, vegetative reproduction increases. Moreover, root sprouts do not appear in diploids. My PhD project focuses on: - Root sprout formation and growth: investigating the triggers behind the formation, anatomy and phytohormones of root sprouts. - Inheritance of clonal traits: studying how clonal traits are passed onto offspring in controlled experiments. - Impact of clonal reproduction on genetic diversity: exploring how increased clonal growth affects the spatial genetic structure of populations of Pilosella rhodopea in the Balkan Peninsula - Effects on reproductive cell development: examining consequences of whole genome multiplication on a female and male gametogenesis and sporogenesis This study, funded by the Czech Science Foundation (GAČR 24-12318S, 2024-2026), will integrate many approaches - from genes to distributional patterns - to provide a comprehensive understanding of how polyploidy alters reproduction strategies in autopolyploids. This will give insight into factors that drive shifts from sexual to clonal reproduction in plants, which is a key survival strategy in many species.

Main author career stage: PhD student

Contribution type: Talk

First choice session: 1. Systematics, phylogenetics, biogeography and evolution

Second choice session: 4. Structure, physiology, and development